* Unusual religions on wikipedia particularly Scientology.
* Rogue waves (it is not that deep of a hole but for some reason I find it interesting).
* Knot theory and category theory (again not sure why).
* Social Psychology on wikipedia
* Ben Thompson's Badass blog (more for humor and a little old now. not sure if it is updated) [1]
* If you are an older mid to late 30 something like me X-Entertainment [2] used to be an awesome rabbit hole (no it is not a porn site). Sadly it is very very broken rabbit hole with collapsed tunnels all over. The author's penchant (Matt) for 80's crap ultimately succumbed to complete utter disorganization and proper backups. It is a 404 wasteland. I recommend googling "x-entertainment and he-man" (yes it is scary to google such terms but trust me)
* Rogue waves (it is not that deep of a hole but for some reason I find it interesting).
* Knot theory and category theory (again not sure why).
* Social Psychology on wikipedia
* Ben Thompson's Badass blog (more for humor and a little old now. not sure if it is updated) [1]
* If you are an older mid to late 30 something like me X-Entertainment [2] used to be an awesome rabbit hole (no it is not a porn site). Sadly it is very very broken rabbit hole with collapsed tunnels all over. The author's penchant (Matt) for 80's crap ultimately succumbed to complete utter disorganization and proper backups. It is a 404 wasteland. I recommend googling "x-entertainment and he-man" (yes it is scary to google such terms but trust me)
[1]: http://www.badassoftheweek.com/list.html
[2]: http://www.x-entertainment.com/index1.html